无法访问子类的方法

Question

I am working on a party game in java.

I struggle to make a proper class hierarchy for cards. The player can carry cards. There are different kind of cards so I made for each card group a separate class. There are the following classes for cards:

• Card (Superclass)
  • NumberedCard (Subclass of Card)
    • NumberedSpecialCard (Subclass of NumberedCard)
  • MasterCard (Subclass of Card)
    • WarriorMasterCard (Subclass of MasterCard)
    • ...

First I construct a NumberedSpecialCard:

NumberedSpecialCard firstPlayerThirdCard = new NumberedSpecialCard(13);

Next I add the card to a list (here firstPlayerCards)

List<Card> firstPlayerCards = new LinkedList<Card>();
firstPlayerCards.add(firstPlayerThirdCard);

Now I create a player object. The player can carry a list of cards.

Player firstPlayer = new Player(firstPlayerMumbles, firstPlayerCards, 1,"Player ONE");

The problem is that i can not access the 'bringMumbleIntoPlay' method which is defined in the NumberedSpecialCard class.

The following does not work:

firstPlayer.getCards().get(2).bringMumbleIntoPlay(allPlayers, firstPlayer, 1);

I do not want to change the class hierarchy (It pictures the real conditions very well.). Can someone help me?

Answer 1

firstPlayer.getCards() is a list of Card s. Now a Card does not have the method bringMumbleIntoPlay in it. So compiler has no idea which subclass it needs to look into . That's why it complains.

One alternative is to use explicit casting with a safety check using instanceof

Card c = firstPlayer.getCards().get(2);
if(c instanceof NumberedSpecialCard){
   NumberedSpecialCard  nsc = (NumberedSpecialCard)c; 
   nsc.bringMumbleIntoPlay(allPlayers, firstPlayer, 1);
}